1. Field of the Invention
The present invention relates to analog MOS transistor circuits. More specifically, the present invention relates to analog MOS transistor circuits useful for analog rectification and correlation of input parameters, such as voltage or current, and for other non-linear differential operations on voltage input parameters.
2. The Prior Art
Circuits are known which have the capability to correlate input parameters, such as voltage or current. A Gilbert multiplier, described in the book Analog VLSI and Neural Systems, by Carver A. Mead, Addison Wesley Publishing Co. 1989, at p. 92, is an example of such a circuit. There are also circuits which compute quadratic or gaussian similarity metrics, such as the circuit described in co-pending application Ser. No. 535,283, filed Jun. 6, 1990. However, there is no circuit known to the inventors which is capable of combining the multiplication function and the gaussian similarity metric.